article · Heliyon
Estimating reference evapotranspiration is vital for sound water resource management, yet standard estimation approaches rely on extensive meteorological datasets that are often absent in data-scarce catchments. In the Awash basin of Ethiopia, simplified temperature-based models were calibrated to overcome these data shortages. Using multiple linear regression alongside modifications to the coefficients and exponents of the Hargreaves-Samani formulation, distinct models were produced for the upper, middle, and lower regions of the basin. The calibrated formulations markedly improved daily estimation accuracy compared to the standard model, reducing root mean squared errors by up to 30.4 percent. Spatial assessments identified higher evapotranspiration rates across the lower and middle plains and lower values across the highland zones. These localized equations provide a dependable means of tracking evapotranspiration using only temperature data, supporting water planning in resource-constrained environments.
Conventional methods for calculating water demand depend on complex climate observations that many developing regions lack. By achieving reliable evapotranspiration estimates with temperature measurements alone, this work provides a practical solution for regional water managers and agricultural authorities working in data-scarce basins, helping improve water allocation and irrigation efficiency without requiring costly meteorological station networks.
This work provides applied and tested mathematical models ready for integration into hydrological planning software, irrigation scheduling tools, and climate risk assessments. The direct users are river basin authorities, irrigation engineers, and agricultural advisory services operating in data-sparse settings. While validated for the Awash basin, translation into software products or commercial advisory platforms would require packaging the regional coefficients into existing digital water management workflows.
AI-generated from the published abstract. Always read the original work before citing.
Reference evapotranspiration is essential for effective water resource planning and management. The Penman-Monteith (PM) method, though widely accepted, requires several meteorological variables that are often unavailable in data-scarce regions. This study aimed to develop and calibrate simplified temperature-based models to estimate ETo in the Awash basin, Ethiopia. Using multiple linear regression and optimization of the Hargreaves-Samani (HS) model through modifying both exponent and coefficients of the original model, new locally calibrated models were developed for the upper, middle, and lower parts of the basin. The calibrated coefficients were 0.0025, 0.0022, and 0.0055, respectively. Compared with the original HS model, the calibrated models substantially improved performance, achieving an average coefficient of determination (R 2 ) of 0.60, Nash-Sutcliffe efficiency (NSE) of 0.60, and index of agreement (d r ) of 0.67 for daily ETo. The root mean squared error (RMSE) was reduced by 17.6, 3.7, and 30.4% in the upper, middle, and lower regions, respectively. Spatial mapping of ETo indicated higher values in the lower and middle plains and lower values in the upper, eastern, and western highlands, reflecting topographic and climatic variability. Overall, the newly calibrated models provide reliable ETo estimation when only temperature data are available, supporting water resource planning in data-limited environments.
This page summarises published work. The authoritative version sits with the publisher.
DOI: 10.1016/j.heliyon.2026.e45378
Is something wrong with this record? Report it or request removal.
Discussion
Have you built on this work, tried to replicate it, or seen it applied in practice? Share what you know. Verified researchers and MARATTO™ domain experts can open a discussion, and any member can reply. Contributions are reviewed before they appear.
No discussion yet. Open the first thread.
New to MARATTO™? Create a free account.
